A group of workers at Australia's detention centres on Nauru say the Australian government knew about physical and sexual abuse of asylum seekers for over a year, but failed to take any action.
In an open letter, 23 current and former employees say the immigration department had tolerated the physical and sexual assault of women and children for more than 17 months.
The signatories include current and former staff for Save the Children and International Health and Medical Services, which were both contracted to provide services at the centres.
The letter said: "We are a group of current and former employees from the Nauru detention centres who have first-hand knowledge of the conditions in which children and adults are detained."
It went on to detail how the department and then-immigration minister Scott Morrison were notified of cases of abuse long before the department initiated the Moss Review, which identified several cases of abuse and sparked a Senate inquiry.
After the Moss Review was released last month, the current minister Peter Dutton said the department had a zero-tolerance for sexual abuse on Nauru.
But the letter's signatories say Mr Dutton's comments do not reflect the attitude or actual response provided to those who reported assault or harassment.
"The Department of Immigration and Border Protection and all service providers were informed, in writing, of several of the assaults detailed in the Moss Review in addition to many other assaults not mentioned in the report.
"In addition to the receipt of formal incident reports, DIBP management participated in weekly and daily meetings where these assaults were discussed," the letter said.
The incidents the letter highlighted include one from November 2013 in which a boy was sexually assaulted by a detention centre employee. The letter said Mr Morrison was notified of this assault, but despite this, the immigration department chose to keep the child in the detention centre where he was assaulted. "Indeed, this child was subjected to further incidents of abuse while he was in detention," the letter said.
It also said that many children showed sexualised behaviour that was symptomatic of abuse.
The signatories have called for the removal of all detainees from Nauru to Australia and for a Royal Commission into sexual abuse and the government's response.